Tools & Resources

The Truth About Mucus

Call it snot, call it mucus, call it a booger -- but don't underestimate what it does for you.

Why Am I Making So Much Mucus? continued...

However, there are times when you do notice your mucus -- usually not because you're producing more of it, but because its consistency has changed.

"Typically, the mucus changes character. It gets thicker," Johns says. "When it has mass effect you feel it, and when you feel it, you want to hock." Some people just naturally have thicker, stickier mucus than others.

It generally takes a bad cold, allergy, or contact with something irritating -- like a plate of nuclear-hot Buffalo wings -- to throw your body's mucus production into overdrive.

For instance, during an allergic response to an offending trigger, such as pollen or ragweed, mast cells in your body squeeze out a substance called histamine, which triggers sneezing, itching, and nasal stuffiness. The tissue of the mucus membranes starts leaking fluid, and your nose begins to run.

Drinking milk may also make some people produce more mucus. Kao says that's due to gustatory rhinitis, a reflex reaction that's triggered by eating. Gustatory rhinitis is also why your nose runs when you eat hot peppers. Milk proteins cause the same type of response in some people. But although you may feel like you have more phlegm, you're not going to worsen a cold by drinking a glass of milk, Johns says.

Why Does My Mucus Change Color?

If you've ever stopped to look at the contents of the tissue after you've blown your nose, you may have noticed that your mucus isn't always perfectly clear. It may be yellow, green, or have a reddish or brownish tinge to it. What do those colors mean?

You might have heard that yellow or green mucus is a clear sign that you have an infection, but despite that common misperception, the yellow or green hue isn't due to bacteria.

When you have a cold, your immune system sends white blood cells called neutrophils rushing to the area. These cells contain a greenish-colored enzyme, and in large numbers they can turn the mucus the same color.

But "you can have perfectly clear mucus and have a terrible ear and sinus infection," Kao says. If you do have an infection, you'll likely also have other symptoms, such as congestion, fever, and pressure in your face, overlying the sinuses, Johns says.